<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
</head>
<body>
    <button type="button">点我消失</button>
    <div><h1>这是标题</h1></div>
    <p class="demo2">hehe</p>
    <p class="demo1">haha</p>
    <input type="text" name="demo3" value="my">
    <script>
        let he = $(".demo2").text();
        console.log(he);
        let text = $(":text").val();
        console.log(text);
        // $("button").click(function(){
        //     $(".demo1").text("hehehe");
        //     $("div").html("<h2>lalala</h2>");
        //     $(":text").val("laila");
        // });
    </script>

    
</body>
</html>